Definition of siren

• n. - One of three sea nymphs, -- or, according to some writers, of two, -- said to frequent an island near the coast of Italy, and to sing with such sweetness that they lured mariners to destruction.
• n. - An enticing, dangerous woman.
• n. - Something which is insidious or deceptive.
• n. - A mermaid.
• n. - Any long, slender amphibian of the genus Siren or family Sirenidae, destitute of hind legs and pelvis, and having permanent external gills as well as lungs. They inhabit the swamps, lagoons, and ditches of the Southern United States. The more common species (Siren lacertina) is dull lead-gray in color, and becames two feet long.
• n. - An instrument for producing musical tones and for ascertaining the number of sound waves or vibrations per second which produce a note of a given pitch. The sounds are produced by a perforated rotating disk or disks. A form with two disks operated by steam or highly compressed air is used sounding an alarm to vessels in fog.
• a. - Of or pertaining to a siren; bewitching, like a siren; fascinating; alluring; as, a siren song.